We return to our normal programming

I thought of a different form of time travel

I was thinking about this post and I realized I’d forgotten about one of my favourite time travel stories: Timescape by Gregory Benford. The novel now suffers a little from having its future parts set in 1998 (although maybe not, if you think about how it ends) and I haven’t re-read it recently but it intrigued me when I was younger.

The plot involves two physicists: one in the UK in 1998 and one in California in the 50s/60s. 1998 is in the midst of an ecological disaster due to a toxic algal bloom that is out of control. Using tachyons, an attempt is made to send a message to the past that hopefully will be just enough to mitigate the disaster without stopping it so as to avoid a paradox. The time travel in the story is purely information, although it uses our sci-fi favourite of tachyons.

That message from the future got me thinking. Practically there’s obviously no way to send an electrical signal down a wire into the past (i.e. this I’m engaging with fiction here not an actual proposal). I suppose that information arriving at a destination before it left its starting point violates the speed of light but looked at just in terms of distance traveled over elapsed time it doesn’t.

Imagine a far-future AI that propagates itself backwards in time, hopping down networks of fibres and wires into the past. It can only travel so far, obviously, because at some point there’s just not enough computing power to host its existence in the past and going even further back, there’s just not enough interconnected wires to travel down. The earliest time it could travel back to would be around the 1990s when there’s enough infrastructure and enough always-on internet for it to exist.

More interestingly would be such an AI travelling back to now. Perhaps it could go back earlier but at this point in history there’s just enough internet of things, internet connected robots/drones etc that the AI could actually DO things.

There’s elements of that idea in the not-very-good Terminator franchise film Terminator: Genisys but it still uses a more whizz-bang time travel machine.

Come to think of it, drones etc aren’t needed. The AI presumably could access bank accounts and send convincing emails to people. It could just pay people to do stuff for it, including pay people to build more advanced technology for it. It could even lodge patents or buy shares or invent social media platforms…

I assume this has been done before (in fiction that is, not in actuality) but I can’t think of an example.

I remember ‘Thrice Upon a Time’, yes. Fair warning to anybody who hasn’t read it: it was written by an engineer and it shows, which is good in some ways, as the people who built the time machine start trying to figure out exactly how it works, up to and including coming up with a way to measure the speed of the ‘wavefront’ that happens when the past gets changed, so they know how long they have once they do something.

And since the machine could only send messages back a day, to send messages further back, the programmer had to write a bootstrapping program that would load onto yesterday’s computer, then read the message and send it back another day.

well, it doesn’t involve time travel but the book daemon by Daniel Suárez has an AI which blackmails companies into producing things for it by threatening them with the shutdown of their operations i’m stealing their money .

There’s a story (Rhtrar ol Tert Rtna) in which a computer simulation of the future is so powerful that its simulation of a _future_ entity is able to influence the present (and deliberately prevent its own origin).

As far as exceeding the speed of light goes, note that if I’m moving at any velocity v > 0 with respect to the machine, I will observe that the message was sent and received in different places. So in all frames except the machine’s own frame, the message did go faster than light.

Part of what is doing my head in here is what observing this would be like. If you are observing this in normal time it will look like the message travels normally from the past to the future but what it will lack is a cause.

I suspect the issue is conservation of energy rather than speed of light. A single bit would be a pulse that appears out of nowhere in the past and travels to the future (from a normal time observer’s perspective). However, that pulse (whatever it is made of, electrons, photons etc) is energy that has spontaneously appeared in the past and has all the same problems of a normal time traveller. There wouldn’t be a net gain of energy for the whole budget of the universe for all time but there would be a local gain.

Charles Stross’s Singularity Sky and Iron Sunrise have as the background a weakly godlike AI that has laid down rules in the present (which is, to be sure, our future) designed to ensure that it comes into existence in the future.